Difference between revisions of "Java - Dynamic Stack Assignment"
From WLCS
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*# pop() removes the value on top of the stack and returns it | *# pop() removes the value on top of the stack and returns it | ||
*# update the '''top''' so that it references its next Node (you need to update top before you return the data) | *# update the '''top''' so that it references its next Node (you need to update top before you return the data) | ||
+ | |||
+ | * '''int top()''' | ||
+ | *# return the value at the top of the stack | ||
+ | *# return Integer.MIN_VALUE if the stack is empty | ||
* '''boolean isEmpty()''' | * '''boolean isEmpty()''' | ||
*# return true if the stack is empty, and false otherwise | *# return true if the stack is empty, and false otherwise | ||
*# Hint: What does '''top''' reference when the stack is empty? | *# Hint: What does '''top''' reference when the stack is empty? | ||
+ | |||
+ | * '''String toString()''' | ||
+ | *# Use a loop to generate the String version of your stack's data | ||
+ | *# return the String | ||
* '''void print()''' | * '''void print()''' |
Revision as of 13:27, 10 November 2016
Contents
Objectives
- You will implement a dynamically-sized queue using linked Nodes
- You will implement queue methods (enqueue/add, dequeue/remove, etc.)
- You will test your dynamic queue in a main() method
Resources
Directions
Before & After Visualizations
- Take out a pencil and paper or a dry-erase board and marker
- Load the Dynamic Stack Visualization
- Consider each of the following questions and use the visualization tool to help you answer them. Practice drawing each of the visualizations yourself.
- What does an empty stack look like? (The top reference variable is null)
- For each of the following actions, assess what the picture looks like Before? then After? What changes occurred to make the Before image become the After image?
- push(4)
- push(2)
- pop()
- pop()
Dynamic Stack class
- Create a new project named DynamicStackProject
- Create a new class called DynamicStack
- Create a new class called Node
- Implement the code for the Node class using Media:Node.java as a guide
- You may want to add a specific constructor that takes in data as a parameter
Attributes
- What attribute must we keep track of when we talk about stacks? (Hint: rhymes with "mop")
- Create a Node reference for the most important stack attribute
- Do not forget to initialize it to null
Methods
- void push(int data)
- push() should not return anything
- push() creates a new Node with the data parameter
- assign the new Node's next reference to the top (so that the new Node is linked to the current top Node)
- update the top to reference the new Node!
- int pop()
- pop() returns Integer.MIN_VALUE if the stack is empty
- pop() removes the value on top of the stack and returns it
- update the top so that it references its next Node (you need to update top before you return the data)
- int top()
- return the value at the top of the stack
- return Integer.MIN_VALUE if the stack is empty
- boolean isEmpty()
- return true if the stack is empty, and false otherwise
- Hint: What does top reference when the stack is empty?
- String toString()
- Use a loop to generate the String version of your stack's data
- return the String
- void print()
- print your entire stack starting at the top (to null)
- Hint: use the for loop that we covered in class
Testing
- You should be able to reuse your main() method from the static stack assignment
- Write a loop that pushes A LOT of data to test the dynamic size
- Write a loop that pops A LOT of data to make sure it works too